Mobile radio technology has experienced a number of generation changes. These generation changes have transformed the cellular landscape into a global set of interconnected networks. It is expected that by the year 2020, cellular networks will support various applications including voice, video, and a complex range of communication services; support is expected for more than 9 billion subscriptions and billions of connected devices.
To account for such increasing the amount on network operability, the third generation partnership project (3GPP) aims to release the next generation of radio access technology, sometimes referred to as 5G. 5G is a set of evolved network technology. 5G intends to provide additional frequency bands and technologies that allow sharing the available frequency spectrum. By this, it is intended to provide new types of applications and services to the users; in particular, industrial applications are envisioned.
Generally, next generation cellular networks are expected to provide efficient support of application with widely varying operational parameters to provide greater flexibility in deploying services and to meet more and more complex performance requirements.
Use cases of communication are transitioning from a person-to-person model to anything-to-anything and anywhere. Cellular networks are expected not only to support communication between individuals, but also communication between objects and things. In particular, communication between devices and sensors is a relevant use case. Such a scenario is often referred to a machine type communication (MTC).
For MTC applications, comparably strict requirements with respect to service availability and reliability are expected. In particular, it is expected that near-zero latency communication is required.
On the other hand, as mentioned above, the number of devices attached to the cellular network is expected to increase even further. This can require to more efficiently utilizing the available spectrum. Increasing capacity and meeting traffic demands is expected to require frequency re-use (frequency sharing). Frequency re-use corresponds to a scenario where communication devices located in neighboring cells of the cellular network transmit data in the same frequency band. However, employing frequency re-use inevitably leads to an increase in the interference level present on the radio interface of the cellular network. In particular, inter-cell interference between neighboring cells is considered to increase. The considerable interference level, on the other hand, can cause problems when seeking to fulfill the above-mentioned requirements with respect to service availability, reliability, and latency. Inter-cell interference is expected to be the dominant source of performance impairment.
To avoid such performance impairment due to frequency re-use, different techniques have been considered. E.g., so-called fractional or soft frequency re-use has been proposed. In such techniques, users are categorized into cell-edge users and cell-center users. Here, cell-center users employ frequency re-use—while cell-edge users transmit on separate frequencies. The categorization of users is based on the location of the user.
However, such techniques face certain restrictions and drawbacks. In particular, while such reference implementations can effectively mitigate interference to fulfill average user performance, a combination of, both, high reliability and low latency is not achievable or only achievable to a limited degree. Further, such techniques cannot be readily applied to MTC scenarios where the coverage area of a cell is comparably small, e.g. in the order of only a few hundred meters. Therefore, soft frequency re-use may not be readily applied for factory automation.